STRTOK(3) BSD Library Functions Manual STRTOK(3)NAME
strtok, strtok_r — string tokens
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <string.h>
char *
strtok(char *str, const char *sep);
char *
strtok_r(char *str, const char *sep, char **last);
DESCRIPTION
This interface is obsoleted by strsep(3).
The strtok() function is used to isolate sequential tokens in a null-ter‐
minated string, str. These tokens are separated in the string by at
least one of the characters in sep. The first time that strtok() is
called, str should be specified; subsequent calls, wishing to obtain fur‐
ther tokens from the same string, should pass a null pointer instead.
The separator string, sep, must be supplied each time, and may change
between calls.
The implementation will behave as if no library function calls strtok().
The strtok_r() function is a reentrant version of strtok(). The context
pointer last must be provided on each call. The strtok_r() function may
also be used to nest two parsing loops within one another, as long as
separate context pointers are used.
The strtok() and strtok_r() functions return a pointer to the beginning
of each subsequent token in the string, after replacing the token itself
with a NUL character. When no more tokens remain, a null pointer is
returned.
EXAMPLES
The following uses strtok_r() to parse two strings using separate con‐
texts:
char test[80], blah[80];
char *sep = "\\/:;=-";
char *word, *phrase, *brkt, *brkb;
strcpy(test, "This;is.a:test:of=the/string\\tokenizer-function.");
for (word = strtok_r(test, sep, &brkt);
word;
word = strtok_r(NULL, sep, &brkt))
{
strcpy(blah, "blah:blat:blab:blag");
for (phrase = strtok_r(blah, sep, &brkb);
phrase;
phrase = strtok_r(NULL, sep, &brkb))
{
printf("So far we're at %s:%s\n", word, phrase);
}
}
SEE ALSOmemchr(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3), strsep(3),
strspn(3), strstr(3), wcstok(3)STANDARDS
The strtok() function conforms to ISO/IEC 9899:1990 (“ISO C90”).
AUTHORS
Wes Peters, Softweyr LLC: ⟨wes@softweyr.com⟩
Based on the FreeBSD 3.0 implementation.
BUGS
The System V strtok(), if handed a string containing only delimiter char‐
acters, will not alter the next starting point, so that a call to
strtok() with a different (or empty) delimiter string may return a
non-NULL value. Since this implementation always alters the next start‐
ing point, such a sequence of calls would always return NULL.
BSD November 27, 1998 BSD